<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <!-- 使用ajax进行登录：
​         2个输入框 一个登录按钮
​         提交字段有 username , password
​         正确得用户名：web2112 密码：jiayou2112
​         接口地址： https://liu.zzgoodqc.cn/login POST方法请求 -->
    用户名：<input type="text" id="user">
    
    密码：<input type="password" id="passworrd">
    <button id="login">登录</button>
</body>
<script>
    window.onload = function () {
        document.getElementById('login').onclick = function () {
            var username = document.getElementById('user').vlaue,
                password = document.getElementById('password').vlaue

            var xhttp = new XMLDocument()
        }
    }
</script>

</html>